In a conventional centralized telecommunications switching architecture, the entire system and its functionality are centralized in one location. Telecommunications devices, such as telephones, computers and facsimile machines, are generally remotely located and are connected to ports within the central switch by transmission lines, or their equivalent, coupled to the devices' transmit and receive channels.
If a process coupled to the central switch wishes to connect two devices, or if a device wishes to communicate with another remote device, a request is sent to the central switch which determines the availability of the remote device(s). If both remote devices are available, the central switch couples the first device's transmit channel to the second device's receive channel and vice versa. These connections are performed at the central switch.
One example of a central switch is a local PBX. Often an organization with a growing work force or customer base requires a locally installed PBX in order to have a more efficient communication network for accommodating the work force and/or the customer base.
Such a PBX can be additionally coupled to an integrated services system such as the system disclosed within U.S. Pat. No. 5,193,110 to Jones et al., which is hereby incorporated by reference herein. Such a PBX-based system can provide interconnections to a plurality of ports or devices providing different types of information services. Other PBX-based systems that traditionally utilize a centrally located PBX are automated call distribution ("ACD") systems, predictive dialing systems and voice mail systems.
However, the initial investment for an organization to install such a PBX or PBX-based system may be prohibitive and expensive, especially if the PBX's potential capacity far exceeds the number of devices or ports initially served. In such a situation, the initial capital expenditure to install the underutilized PBX or PBX-based system may not be recouped for quite some time. An option would be to invest in a smaller PBX-based system and upgrade to a larger system as the need arises. In the long run, this may prove more costly both in money and time.
Another disadvantage to a central switch or a centralized integrated services system is that upon a system or power failure, all ability to provide communications disappears since all of the switching functionality is centralized in one location.
Thus, what is needed in the art is a distributed switching architecture whereby a switching system or integrated services system may be implemented in stages in order to minimize capital expenditures and to grow the system as the need arises.
There is also needed in the art a switching system or integrated services system that will not become entirely inoperative upon the occurrence of a system or power failure.